Constraints on sterile neutrinos and the cosmological tensions

TL;DR

This paper explores how sterile neutrino masses relate to cosmological tensions like Hubble and S8, suggesting that certain extended models can reconcile these tensions and favor a slightly open universe.

Contribution

It demonstrates that extended cosmological models with sterile neutrinos can alleviate the Hubble and S8 tensions and favor a non-flat universe.

Findings

Sterile neutrino masses are inferred at 2σ in some models.

Extended models reduce the Hubble and S8 tensions.

A slightly open universe may be preferred with sterile neutrinos.

Abstract

We investigate cosmological bounds on sterile neutrino masses in the light of the Hubble and $S_8$ tensions. We argue that non-zero masses for sterile neutrinos are inferred at 2$\sigma$ level in some extended models such as varying dark energy equation of state, when a direct measurement of the Hubble constant $H_0$ and weak lensing measurement of dark energy survey (DES) are taken into account. Furthermore, the Hubble and $S_8$ tensions are also reduced in such a framework. We also consider the case where a non-flat Universe is allowed and show that a slightly open Universe may be favored in models with sterile neutrinos in the context of the cosmological tensions.